Spraying oil on a lit gril is very dangerous, as major flare-ups can occur. The paper towel method should work. If your grates are so rough that they shred a paper towel, I would say they are not clean,, and you're cooking on left-over pieces of food from previous cooks, an unpleasant thought. If you heat your grill hot enough, all the debris is reduced to ash, and is easily brushed off. I have never worked with cast iron grates, so perhaps they get pittted somehowand are therefore rough, but I know this doesn't happen to properly cared for cast iron skillets. I have never encountered this with grates of any other material. I suggest you work on getting tyour grates clean and smooth on top, even if it takes a major cleaning and re-seasoning. Then use a paper towel.

My grill has cast iron grates and I use the paper towel trick to oil the grates and have no problems. I must agree that if your grates are rough you must not have clean grates. To clean the grates off each time I simply turn the grill on high for a couple of minutes and eveything turns to ash and then I brush off with a brass brush. You can also put the grates in your self cleaning oven and run it through the cleaning cycle.

Come to think of it YB, I too seem to be on an endless quest to find a QUALITY oil sprayer. My last one was a $10.00 aluminum one from Williams-Sonoma. I wipe my grates with a oil soaked folded papaer towel with tongs but use the oil sprayer for the food sometimes.

O.K. if you don’t like the paint sprayer idea, try this one:
Chapin 48 Oz. Multi-Purpose Hand Sprayer Model 1002, available at Home Depot for $7.99.
You can view it at there web site (it wouldn't let me post the link).

Sorry, I've already tried it and Lowes equal. Pumped it up to 100 times and all it does is squirt a pitiful stream of oil. I am, and apparently a few others, lookng for something that will atomize oil fine enough to lube a larger grill. I am trying to oil one 36" wide by 20" deep and the paper towel method doesn't work. (and my grates are CLEAN!!!)

Thanks for the info and ideas. First off, The grates ARE clean No chunks, no crud, etc..

Maybe it's just cheap paper towels falling apart.
Lately, I've been using a 3" natural bristle paintbrush to oil the grates. When done it goes back in it's zipper bag and into the freezer till next time. I keep several basting brushes frozen as well. There is a thread about it somewhere.

I know Yard Burner said NO PAM, but I it's always worked for me. On my charcoal grills I lift the grate with a pair of channellocks turn away and spray. On my gas grill which has a bigger grate, I use two pairs of channellocks and have my wife spray the grate.